I dont think if you cant find your old password you can upgrade no matter where you buy it from. Unfortunately I think you will have to buy a full new license. Good news is that its now using Syncrosoft USB key so you can install it 100000 times if you want as long as you keep your key.
As far as where to buy it from, did you try www.sweetwater.com ? I dont know how it works for overseas purchases but sweetwater has the most amazing people and support, plus they send you candy in the box!